#include <fstream>
#include <algorithm>
#include <string>
#include <cstring>

using namespace std;

ifstream fin("ballg.in");
ofstream fout("ballg.out");

int n, m;
const int maxn = 30 + 10;
int f[maxn][maxn];
int main()
{
	memset(f, 0, sizeof(f));
	
	fin>>n>>m;
	
	f[2][1] = 1;
	f[n][1] = 1;
	for(int j=2;j<=m;j++)
		for(int i=1;i<=n;i++)
		{
			if(i==1)
			{
				f[i][j] = f[n][j-1] + f[2][j-1];
				continue;
			}
			if(i==n)
			{
				f[i][j] = f[1][j-1] + f[n-1][j-1];
				continue;
			}
			f[i][j] = f[i-1][j-1] + f[i+1][j-1];
		}
	
	fout<<f[1][m]<<endl;
	
	fin.close();
	fout.close();
	
	return 0;
}